Factors Associated With Sputum Non-conversion After Intensive Phase of Treatment Among Pulmonary Tuberculosis Patients: a Nested Case-control Study, Kirinyaga County, Kenya, 2021
- Respiratory Diseases
Background: Persistent sputum positivity is a driver of TB transmission. We observed a 2-fold increase in non-conversion from 3.0% in 2018 to 7.0% in 2019 despite a reduction in the incidence (24.6/10,000 persons–22.3/10,000 persons) in Kirinyaga County. We identified factors associated with non-conversion after the intensive phase of treatment.
Methods: We reviewed records from TB register for pulmonary TB patients from July 1, 2019–May 31, 2021. A case was any person with a positive sputum test at diagnosis and still positive following the intensive phase of treatment, while a control was any person with negative test results. Cases and controls were sequentially selected from the abstracted records and interviewed using a structured questionnaire. We used logistic regression to identify independent factors associated with non-conversion.
Results: The number of PTB records abstracted was 765, of which 600 (78.4%) were for male patients. The median age was 38 years. The number of patients with a negative sputum test following the intensive phase and who were cured after treatment completion was 304 (50.0%), none was resistant, and 5 (5.1%) had failed treatment. Among the sputum-positive patients, 53 (54.1%) were cured, 7 (7.1%) were resistant, and 10 (10.0%) failed treatment. The sputum non-conversion rate was 13.9%. We selected 69 cases and 138 controls from abstracted records. The odds of sputum non-conversion were 3.6 times higher among alcohol users than among non-alcohol users (aOR=3.6; 95% CI=1.66–8.05). Other risk factors were weight loss (aOR=5.4; CI=1.95–15.09) and high initial bacterial load (aOR=8.1; CI=3.21–20.54), while knowledge on infectiousness (aOR=0.2; 95% CI=0.08–0.47) was a protective factor.
Conclusions: Drug resistance and treatment failure were observed in patients with prolonged sputum positivity. Risk factors were high initial mycobacterium load, alcohol use, and weight loss. Avoidance of alcohol use during treatment and reduction in weight loss could improve sputum conversion.
Methods: We reviewed records from TB register for pulmonary TB patients from July 1, 2019–May 31, 2021. A case was any person with a positive sputum test at diagnosis and still positive following the intensive phase of treatment, while a control was any person with negative test results. Cases and controls were sequentially selected from the abstracted records and interviewed using a structured questionnaire. We used logistic regression to identify independent factors associated with non-conversion.
Results: The number of PTB records abstracted was 765, of which 600 (78.4%) were for male patients. The median age was 38 years. The number of patients with a negative sputum test following the intensive phase and who were cured after treatment completion was 304 (50.0%), none was resistant, and 5 (5.1%) had failed treatment. Among the sputum-positive patients, 53 (54.1%) were cured, 7 (7.1%) were resistant, and 10 (10.0%) failed treatment. The sputum non-conversion rate was 13.9%. We selected 69 cases and 138 controls from abstracted records. The odds of sputum non-conversion were 3.6 times higher among alcohol users than among non-alcohol users (aOR=3.6; 95% CI=1.66–8.05). Other risk factors were weight loss (aOR=5.4; CI=1.95–15.09) and high initial bacterial load (aOR=8.1; CI=3.21–20.54), while knowledge on infectiousness (aOR=0.2; 95% CI=0.08–0.47) was a protective factor.
Conclusions: Drug resistance and treatment failure were observed in patients with prolonged sputum positivity. Risk factors were high initial mycobacterium load, alcohol use, and weight loss. Avoidance of alcohol use during treatment and reduction in weight loss could improve sputum conversion.